Method of cutting a joint in a ceiling tile

ABSTRACT

Conventional ceiling tiles are provided with tongue and groove joints for interconnecting a plurality of tiles together. The method herein is directed to the technique for cutting the joints in a ceiling tile. The method comprises the prescoring of the painted board face surface immediately prior to the joint formation. This permits a very uniform edge to be formed at the joint-face surface interface without disruption of the painted face surface of the tile.

United States Patent Garrick et al. Jan. 1, 1974 [54] METHQD ()F CUTTING A JOINT IN A 3,362,294 1/1968 Oxel 144/136 X 3333333 if 5"" 144/309 yan [75] Inventors: John R. Garrick, Lancaster; Jerald E. Miller, Fleetwood, both of Pa. P E D M R S h rzmary xammer ona c ran [73] Assignee: firmstrong lElork Company, A cliff d 3 price ancaster, a.

[22] Filed: Oct. 30, 1972 [57] ABSTRACT [21] Appl. No.: 302,248

Conventional ceiling tiles are provided with tongue and groove joints for interconnecting a plurality of [52] 144/323 144/91 3 27 tiles together. The method herein is directed to the technique for cutting the joints in a ceiling tile. The l' y g method comprises the prescoring of the painted board 144/9 9] A R A R 3 face surface immediately prior to the joint formation. This permits a very uniform edge to be formed at the joint-face surface interface without disruption of the [56] uNlTE g gszg s giiENTs painted face surface of the tile.

3,289,714 12/1966 Aammer 144/91 X 1 Claim, 1 Drawing Figure BACKGROUND OF THEINVENTION 1. Field of the Invention The invention hereinis directed toa methodof forming a ceiling tile and, more particularly, to amethod of cutting a joint structure-kin the sidezof a ceiling tile.

2. Description of thesPrior Art In the prior art, the fabrication of the jointdetail of a ceiling tile is accomplished byatenoning operation. in this operation, a cutting :tool is formed with the desiredcross-section and tthis 'tool is used to cut thedesired joint in the side of a ceiling tile. Normally,the width of the cutting tool is slightly greater than the thickness of the ceilingttileso that the square edge between the face surfaceof'the ceilingtileand .the side of the ceiling tile is formed by :the sametool which cuts the joint detail in'the edge of .the ceiling tile.

Prior art techniques wereaccompanied by aconsiderable amount of paint flakingalong the .edge of the ceiling tile above described. 'For this reason, production of tile was restrictedto patterns, colors, and techniques which would disguise the flaked edges of ceiling tile when the ceiling tile was installed in position.

SUMMARY OF THE lNVENTlON The invention herein comprises the prescoring of the painted surface of a ceiling"board,immediatelyrprior to the joint formation. A diamond saw is used 'to cut through the painted face surface at thepoint where the edge is to be formed between thepaintedface surface and the side of the ceiling tile. This diamond sawforms the edge between the sideand face-surface and because 7 it is cut by a saw perpendicular tothe face of the ceiling tile, there is no'flaking of the paint on the edge at the painted face surface of the ceiling .tile. Conventional tenoner cutters are then used'to cutthe joint configuration in the side of the ceiling tile. The tenoners now provide only the joint configuration and do'not form 'the edge of the ceilingatile between the side of the ceiling tile and the painted-face surface of the ceiling tile. As a'result of the above-described method,.the problem of paint flaking along the edge of the ceiling tile at the painted face thereof has been eliminated.

BRIEF DESCRIPTION OF THE DRAWING The FlGURE of the drawing is aside view oftheapparatus used for carrying out thexmethod .of the invention herein. a

DESCRlPTlON QF THE PREFERRED EMBODIMENT Referring to the drawing, there is shown the conventional ceiling tile 2. This ceiling tile is provided with the so-called tongue and groove joint configuration. This means that on one side of the ceiling tile there is 'provided a tongue 4 which is formed on the ceiling tile in such a position that-it can be inserted into a groove on an adjacent ceiling tile. The groove on the adjacent ceiling tile will be formedin themanner of groove 6 of ceiling tile 2. lnto'this groove6 there'would be inserted a tongue of another tile similar to'tongue 4 of ceiling tile 2. This particular tongue and groove ceiling tile joint is conventional in the art and has been used for a large number of years. Theiback 8 of the ceilingtile is normally unpainted and is always obscured from view when the ceiling tile is mounted in position. The front face surface 10 of the ceiling .tile will-always be visible to the viewer of the ceiling. Normally, theedge 12of a conventional ceiling tile wouldnot appear as asharp edge in the plane of-the face 10 of the ceiling tile, but would normally be a'recessedarea. This was'normally done because theconventional techniquesforforming the side joint in theceiling tile would result in the "formation of an edge 12 which would haveflakedpainton the surface 10. This wouldexistbecause theznormal cutting tool which would form the edge '12 would be moving-in a-directionin .the plane of theface 10.- Consequently, the cuttingtool would'be rubbing and cutting the edge 12 in a direction perpendicualr to-the side of the board, but across the grain of the fiberslayingin the face 10 of the board. This type of cutting action would tend todislodge fibers and :paint from the face 10 of the ceiling board at the edge 12. This can cause the product to be rejected. This flakedpaint effect can be concealed by having the edge 12 recessed below the face plane 10 so that therewouldactually appear to be agroove between two adjacenttile structures. Also, it may be camouflaged bycoloring techniques or design patterns.

However, the trend'nowadays is.to provide'a ceiling tile arrangement wherein the tile'is positioned in such a manner that the ceiling tile appears to be one large continuous surface. When this technique is utilized, the edge 12 must be in the plane of face 10 of the ceiling tile. There is thus then no easy'way of concealing flaked paint along the edge 12.

By'the below-described technique,it-is now possible to'make a ceiling tile with a face 10that does not have a flaked paint effect along the edge 12 of the tile. The method is carried out'by first cutting or prescoring the face 10 of the ceiling tile with a diamond or like-abrasive type saw 14 which is'mounted'perpendicular to the face 10. This saw will prescore the ceiling board to a depth of approximatley l/ l 6 inch and will actually form'the edge 12 of the finished ceiling board. A particularly useful saw structure for carrying out the prescoring operation is a saw with a 60 to 120 grit diamond cutting edge operating at aobut 3,700 revolutions per minute and at a board feed rate of feetper minute. Two saw blades would'be mounted in position and the distance between two adjacent saw blade edges would be equal to the final face dimension of the ceiling tile. After the ceiling tile has -been prescored, then the tongue and groove edge configuration is formed.

It is conventional in the art to form the'tongue .and groove edge configuration through the use of edge cutters or tenoner cutters. As-shown in the drawing, a cutter with a cross-section similar to that of cutter 16 is used to cut thegroove edge of the ceiling tile while a cutter similar to that of cutter 18 is used to cut the tongue section of the ceiling tile. These cutters rotate in a plane which is the same asthe plane of the ceiling board and the cutters move along the side of the ceiling board forming the tongue and groove configurations. However, it should be noted that the edge 20 of both cutters does not actually-cut the board since the board has already been cut away in that area by the prescoring operation. The prescoring operation, by extending approximately l/l6 inch into'the board structure, has formed approximately l/l6 inch of the side joint configuration. The tenoner cutters simply touch this 1/16 inch edge without cutting any additional material off the ceiling tile. The rest of the tenoner cutters do cut into the tile and form the appropriate joint configuration. Because the tenoner cutters are not cutting immediately adjacent the tile side of edge 12, there is no stress being placed on the fiber construction and paint coating of the edge 12 to provide any edge flaking of the paint on face surface 10. There is then provided a finished product which is quite capable of being mounted adjacent a second finished product so that the edge 12 of each product will abut each other in the same general plane without any roughness to the edges 12.

What is claimed is:

l. The technique for forming the joint side configuration of a conventional ceiling board wherein the side configuration is normally formed by the step of cutting the side configuration of the ceiling board with a shaped cutter which extends along the side of the ceiling board and is positioned in the plane of the celing board and rotates within the plane of the ceiling board while cutting the appropriate joint side configuration to the board, the improvement of prescoring the ceiling board from its painted face surface by a cutting means which extends perpendicularly from the face surface of the ceiling board and said cutting means partly cuts into the ceiling board to form the finished edge of the ceiling board face surface and the side of the ceiling board containing the appropriate joint configuration. 

1. The technique for forming the joint side configuration of a conventional ceiling board wherein the side configuration is normally formed by the step of cutting the side configuration of the ceiling board with a shaped cutter which extends along the side of the ceiling board and is positioned in the plane of the celing board and rotates within the plane of the ceiling board while cutting the appropriate joint side configuration to the board, the improvement of prescoring the ceiling board from its painted face surface by a cutting means which extends perpendicularly from the face surface of the ceiling board and said cutting means partly cuts into the ceiling board to form the finished edge of the ceiling board face surface and the side of the ceiling board containing the appropriate joint configuration. 